Keyboards are important and popular input mechanisms for providing input to a variety of computing devices. Notwithstanding the development of various alternative human input technologies, such as touchscreens, voice recognition, and gesture recognition, to name only a few, keyboards remain the most commonly used device for human input to computing devices. Of the mechanical variety, keys may come in several types, including, but not limited to, membrane-based keys, dome-switch keys, scissor-switch keys typically used in laptops today, and mechanical-switch keys. FIG. 1 shows an isometric view of a common telescopic-switch key 100 including a keycap 102 and a telescopic keyswitch mechanism 104 coupled to the keycap 102. FIG. 2 shows an isometric view of a common scissor-switch key 200 including a keycap 202 and a scissor-type keyswitch mechanism 204 coupled to the keycap 202. Both have proven to be effective keyswitch mechanisms.
FIG. 3 shows a side elevation view of the key 100 shown in FIG. 1 through section line A-A. The key 100 includes the keycap 102, the telescopic keyswitch mechanism 104 coupled to the keycap 102, a base 300 coupled to the keyswitch mechanism 104, and a spring 302 used to bias the keycap 102 into an operating position. The spring 302 biases the keycap 102 by imparting a force on the keycap 102 relative to the base 300 such that the keycap 102 resists being pressed toward the base 300 when the key 100 is actuated by a user. Spring 302 may be designed to “buckle” upon sufficient force applied to the key 100 whereby a snapping action provides a tactile sensation to a user actuating the key 100. A mechanism may be provided for detecting a keystroke upon actuation of the key 100 by a user. Such a mechanism for detecting a keystroke may include, but is not limited to, a pair of contacts that close to complete an electrical circuit, a capacitive sensor assembly comprising electrodes with varying mutual capacitance which changes with relative movement of a metal piece on, or in, either the keycap 102 or the base 300, and similar mechanisms. Furthermore, although a three-stage keyswitch mechanism 104 is shown, which provides a more dramatic collapsing effect, a two-stage mechanism is often used in keys with this design.
In order to keep up with consumer demand for smaller, more portable computing devices, keyboard designs have also moved toward correspondingly thinner and smaller designs. Making the keyboard smaller with respect to the total area of the keyboard works in tension with the need for keyboards to remain usable given the size constraints of the human finger that is used for actuating the keyboard elements, or keys. The thickness of the keyboard, however, can still be improved to provide a thinner, sleeker design for either the computing device in which it is embedded, or the keyboard peripheral itself, making for improved portability of the device.
In addition to designing the keyboard as thin as possible, some attempts have been made to collapse a keyboard when it is not in operation in order to further minimize the thickness of the keyboard while it is in a stored position. FIG. 4A illustrates one solution. FIG. 4A shows a side elevation view of the key 200 shown in FIG. 2 through section line B-B. The key 200 includes the keycap 202, the scissor-type keyswitch mechanism 204 coupled to the keycap 202, a base 400 coupled to the keyswitch mechanism 204, and a dome-type spring mechanism 402 to bias the keycap 202 into an operating position. In this arrangement, both a dome-type spring mechanism 402 and a lower right sliding leg of the scissor-type keyswitch mechanism 204 may be moved in a direction parallel to a plane of the base 400 to allow the key to collapse. FIG. 4B illustrates an alternate solution where a spring 404 for biasing the keycap 202 into an operating position is coupled to the lower right sliding leg of the scissor-type keyswitch mechanism 204 and is moved in a direction parallel to the plane of the base 400 to allow the key to collapse. These known approaches, however, have yet to be successfully commercialized.
Another approach to minimizing the thickness of a keyboard is to reduce the travel distance for the keys (i.e. the distance that a keycap travels upon actuation in order to register a keystroke). FIG. 5 illustrates a force-to-displacement function of a typical spring (e.g. a dome spring) used in current keyboards. Assuming a travel distance of 2 mm for actuating the key, the rising part of the curve on the left side of the graph shown in FIG. 5 corresponds to roughly 1 mm of initial travel before the snap point of the key. Since this initial travel distance does not contribute to the actuation of the key in order to register a keystroke, the travel distance of current keyboard designs that include this initial travel distance may have a thickness dimension that can be reduced by at least this initial travel distance. The claimed subject matter, however, is not limited to implementations that solve any or all of the aforementioned disadvantages.
Furthermore, an ultrathin keyboard is prone to be relatively lightweight by itself. Consequently, when an ultrathin keyboard is integrated with a slate-like computing device, for example, the weight distribution may become an issue. Specifically, the center of gravity of such an integrated device is often located such that the integrated device is unstable in an operational configuration. In addition, various existing designs for integrating keyboards with slate computers enable limited, or no, options for adjusting the viewing angle for the display when the device is in an operational position. The claimed subject matter, however, is not limited to implementations that solve any or all of the aforementioned disadvantages.